Background and Goal of Study: Endarterectomy (CEA) is the standard treatment of carotid stenosis. Continuous EEG is one of the monitoring used to detect cerebral ischemia (1). When this appears, the EEG changes and the hemodynamic variations induced either spontaneously or by the anesthesiologist are not described. We therefore reviewed the peroperative electronic records of our patients anaesthetised for CEA to describe these modifications.
Materials and Methods: This is a retrospective single institution study, approved by our IRB, that reviewed the data recorded by our anesthesia information management system (Innovian Anesthesia Drager) in 275 patients who underwent CEA from 01 2012 till 12 2016. All the cases were performed under general anesthesia with propofol and remifentanil controlled by TCI using respectively the Schnider or the Minto model. A continuous EEG using 10 leads placed as described by the "10-20" international system was used in all the cases. The EEG was continuously observed by a neurologist and a written summary was avalaible in the medical record system. The cases for which an EEG modification was noted around the clamping time of both the internal and external carotid have again been thoroughly reviewed by a single neurologist (NG) to confirm the changes and the exact timing of the event. The mean blood pressures (MPB
mmHg) were extracted from the database 20 minutes before and after the event. ANOVA for repeated measures was used to compare MBP.
Results and Discussion: 29 (10,54%) patients presented significative EEG changes (EEGdelta group). 27 of them required to bypass the clamp with a shunt and only 2 responded positively to an increase in MBP. The MBP recorded during the clampling was however significantly higher in the EEGdelta group (96.8 (+/- 12.0) vs 89.6 (+/- 9.6) (p=0.001). The most frequently reported EEG change was a isolated lateral attenuation (72% of EEGdelta); occuring mostly in the first 20 seconds. The patients with a collateral stenosis > 80% showed more EEG changes (P=0.045). None of the other recorded peroperative data were associated with EEGdelta.
Conclusion: An increase in MBP was observed in the EEG delta group, however most of these still required a shunting. The cause of this modification is not obvious from our data and shoud be further studied.
References: 1.Pinkerton JA. EEG as a criterion for shunt need in carotid endarterectomy. Ann Vasc Surg. 2002;16(6):756-61.

11 / Hemodynamic modification and EEG monitoring during carotid surgery: a review of the hemodynamics and the neurological perioperative complications in 275 consecutive cases.